At this week’s G8 summit, the prime minister has a great opportunity to take the lead in tackling poverty

It is tempting to wonder how much of an appetite Barack Obama will have for dinner on Thursday evening. That afternoon, ahead of the two-day meeting of the G8 at Camp David, which kicks off on Friday, he will announce what is currently being called “the new alliance to increase food security and nutrition”.

It’s an initiative by members of the G8 designed to tackle hunger in half a dozen African nations, which has been the subject of intense inter-governmental back channel negotiations for the past few weeks. Obama is rightly famed for the power of his oratory but, if ever there was a moment for more than empty words, it is now. With food commodity prices spiralling upwards in a way not seen since the devastating price spikes of 2008, millions of lives literally depend upon it. And when Obama sits down to eat, he will know that.

The plan as it stands this weekend is for a programme designed to lift 50 million people out of poverty across six African nations: Ethiopia, Ghana, Tanzania, Mozambique, Ivory Coast and Burkina Faso. Detail is predictably hazy and hardly innovative. It involves individual nations investing in the agricultural base from a macro level – large-scale irrigation schemes – through to the micro level of training for individual farmers and access to more robust seed stock, all of it intended to increase output and hence income.

That 50 million figure makes it sound like an ambitious initiative but, compared to the scale of the global problem, it can’t help but feel meagre. There are 170 million children alone who are suffering from chronic malnutrition, which leads to physical and intellectual stunting. Add the adults also at risk and we head towards a figure of one billion people without enough to eat.

There is also concern among aid charities over the approach. Focusing on economics – the notion of lifting people out of poverty – is all well and good but without solid nutritional goals it doesn’t stand for much and, while nutrition is likely to be mentioned in the announcement, there are unlikely to be any hard numbers. Then there is the mechanism for making it work. Where is the money to pay for it all coming from?

The Obama White House’s struggles over international aid budgets are well known and for a while during negotiations the US was pleading poverty. Objections from other G8 members, including Britain, appear to have loosened the purse strings, but will it be enough? And how will the programme be expanded beyond the initial half a dozen or so nations? “The initiative is definitely a step forwards,” says Brendan Cox, director of policy and advocacy at Save the Children. “But it needs to be a down payment. It’s far from commensurate with the scale of the crisis.”

Indeed. The fact is that we have been here before. At the L’Aquila G8 summit in 2009, the member countries and five other donors pledged $22bn for food security and agricultural initiatives over three years. But there was no clear schedule for payments and by last July only 22% of that much-needed money had been spent. That can’t happen again.

The situation is made all the more urgent by what’s happening on the commodity markets, with analysts warning that we are at serious risk of a situation even worse than the food price spikes of 2008. On Friday, soybeans were trading at around $545 a ton in Chicago, just shy of the historic high in July 2008 of $552, partly because of droughts across South America, which produces 55% of the global crop. Prices for rapeseed oil and corn are not far behind them.

The problem is that the grain reserves that used to be maintained around the world are now a thing of the past and it would take only one more shock – storms across Russia’s wheat fields, droughts in the American west – for food price inflation to flare out of control again. It would lead to the sort of civil disturbances we saw last time which, in turn, are credited with initiating the Arab spring. Food security is no longer just about the human imperative of having enough to eat. It impacts on both governance and the very structure of society. Certainly the impact on the African nations the G8 is pledging to help would be dramatic.

There is also a question over presentation. Obviously much of the heavy lifting for G8 summits is done beforehand by the so-called government “sherpas”. But by announcing this food security initiative before the heads of state have even sat down at the table, it does makes it sound like a done deal, however flawed it may be.

Here, there is a massive opportunity for David Cameron, who is already highly regarded in international aid circles for the way he has committed himself and the coalition government to maintaining aid budgets, despite the savage cuts that have been instituted elsewhere. (Although a failure to include a commitment to maintain aid at 0.7% of national income in last week’s Queen’s speech was noted, interpreted by the more generous as an attempt not to provoke the right of the Tory party rather than as a failure of will.)

The prime minister is credited with having played a major role in saving millions of lives last year, by throwing both his leadership and hard British cash behind a programme to provide vaccines for 250 million of the world’s poorest kids. It is no accident that Cameron was last week named a co-chair of the United Nations panel charged with framing a new set of development goals when the current ones expire in 2015.

His job now is to sit down at the table at the G8 and make sure that Obama’s announcement is merely a starting point; that the talking shop doesn’t become a place where a bunch of world leaders rubber-stamp agreements made elsewhere by their underlings because they make for good soundbites. Promisingly, it was announced last week that the leaders of a number of the African countries being targeted by the programme have been invited to join the talks at Camp David on the second day of the summit.

Presumably they don’t want to come all that way merely to hear the American president say to them in person what he said to the world two days before. They know the scale of the problem, for it is their people who are dying. Undoubtedly they will make their own case: for proper funding, for nutritional goals, for a way to roll out the plan beyond the initial six.

But they will need the support and advocacy of a leader from within the wealthy developed nations who make up the G8. Given his record, it is clearly a job for David Cameron. It is a role the British prime minister cannot shirk. Too many lives depend upon it.